Leading Research Scientist, Institute of Applied Problems of Physics, NAS of Armenia, Republic of Armenia

Speech Title: Crystalline compounds of dimethylglycine with polar symmetry
Abstract: Among salts of glycine and its N-methyl derivatives salts of N,N-dimethylglycine (DMG) were less studied [1]. Crystal structures of dimethylglycinium chloride (DMGH)Cl [2], dimethylglycinium trifluoroacetate (DMGH)(CF3COO) [3], molecular adduct DMGellagic acid [4] and of a compound of dimethylglycine with squaric acid [5] were determined. All these crystals have centrosymmetric structures. We undertook a systematic work on obtaining and investigation of crystalline salts and molecular adducts of dimethylglycine. In results of investigation of reaction of dimethylglycine in water media with various inorganic and organic acids numerous crystalline compounds: simple salts, salts with dimeric (DMG...DMGH) cation and adducts were obtained. The majority of obtained salts has centrosymmetric structure, however, some of them crystallize with polar symmetry: (DMG...DMGH)Cl (space group P21), (DMG...DMGH)Br (P21), (DMG...DMGH) maleate (P21), (DMGH) maleate (Pna21), (DMGH) (maleic acid...maleate) (Pca21), DMG.L-tartaric acid (P21), DMG.D-tartaric acid (P21). Two of them, (DMG...DMGH)Cl and (DMG...DMGH)Br, are new ferroelectrics [6].
Keywords: salts of amino acids; crystal structure; ferroelectrics